Currently, in the MBMS field, an MBMS notification procedure is used, by a base station at a network side (which refers to an NB before Release 8 or to an eNB in Release 8 and thereafter), to notify a User Equipment (UE) of an incoming MBMS service or change of an MBMS Control Channel (MCCH). In an access network, this is referred to as an MCCH information change notification.
In current cellular systems, it is specified that a UE interested in receiving MBMS services has to periodically check the MCCH information change notification. In a WCDMA system, an indicator of MCCH information change notification is sent over an MBMS Indication Channel (MICH). For a Long-Term Evolution (LTE) system (namely, a system in 3GPP Release 9 and thereafter), the indicator of the MCCH information change notification is sent over a Physical Downlink Control Channel (PDCCH).
Further, after receiving the MCCH information change notification, the UE interested in receiving MBMS services acquires new MCCH information immediately from the start of a next modification period, i.e., reads the MCCH to acquire detailed MBMS control information for receiving data. As known to those skilled in the art, the MCCH information uses a configurable repetition period to perform periodic transmissions.
Besides the MCCH information change notification, the current LTE system further defines events that likely trigger the MCCH reading, for example, the UE being powered on or the UE entering into a new cell. In other words, when the two cases occur, the UE needs to immediately read the MCCH. Such design is to prevent the UE from missing any MCCH information change notifications in the two cases.